Explanation:
(a): √8 = √4√2 = 2√2. => k = 2
(b): √50 = √25√2 = 5√2. => k = 5
(c): √98 = √49√2 = 7√2. => k = 7
(d): √12 = √4√3 = 2√3. => k = 2
(e): √300 = √100√3 = 10√3. => k = 10
(f): √45 = √9√5 = 3√5. => k = 3
(g): √125 = √25√5 = 5√5. => k = 5
(h): √28 = √4√7 = 2√7. => k = 2